The present invention relates to a novel magnesia adsorbent and a method for treating waste water containing organic contaminants utilizing the same.
Hereinbefore, there have been known methods for obtaining magnesia by calcining magnesium compounds, such as magnesium hydroxide, basic magnesium carbonate and the like, which produce magnesia by thermal decomposition. However, all of known magnesias have been obtained by calcining at high temperatures of 800.degree.-900.degree. C. or more.
Meanwhile, waste water drained from various chemical plants, such as pulp mill waste water, bleaching waste water, waste water from food manufacturing plants, humic substances containing water and dye works waste water, contain organic substances which cause environmental pollution. For instance, pulp mill waste water contains a great quantity of lignin and its derivatives and divatured hemicellulose, and, accordingly, the chromaticity becomes remarkedly bad and the COD value and the BOD value become remarkedly high. Therefore, when discharging to rivers, removal of such contaminants is required. Hereinbefore, various methods for treating such waste water have been proposed. Among them massive lime method and coagulation method using inorganic flocculants such as aluminium salt, iron salt and magnesium salt have been known as effective methods. Especially, massive lime method has been known as one of the most effective methods for treating pulp mill waste water. However, such known methods are not yet sufficient and have disadvantages in removing efficiency of contaminants, sedimentation efficiency of produced flock, dehydrating efficiency of produced slurry and treatment of produced sludge.
An object of the present invention is to solve such conventional defects, and to provide a novel adsorbent showing excellent adsorption properties to such waste water containing organic contaminants and also capable of effectively utilizing for other various adsorption purposes.
An another object of the present invention is to provide a novel magnesia adsorbent which is easily regenerated and showing excellent adsorption properties as compared with conventional magnesia adsorbents.
An other object of the present invention is to provide a novel magnesia adsorbent containing an additive which shows an extending effect without lowering the adsorption properties.
An other object of the present invention is to provide a method for treating waste water containing organic contaminants using above magnesia adsorbent.
Other objects and advantages of the present invention will appear from the following description.